fix issues #423, update version to v1.28.4

CYLTabBarController.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "CYLTabBarController"
-  s.version      = "1.28.3"
+  s.version      = "1.28.4"
   s.summary      = "Highly customizable tabBar and tabBarController for iOS"
   s.description  = "[EN]It is an iOS UI module library for adding animation to iOS tabbar items and icons with Lottie.  [CN]【中国特色 TabBar】一行代码实现 Lottie 动画TabBar，支持中间带+号的TabBar样式，自带红点角标，支持动态刷新。【iOS12 & iPhone XS MAX supported】"
   s.homepage     = "https://github.com/ChenYilong/CYLTabBarController"